Control Software for TOF-SIMS Based on LabVIEW Object Oriented Programming

Time of flight secondary ion mass spectrometer (TOF-SIMS) is a powerful surface analysis technique that has been applied in a wide range of scientific fields. The development of TOF-SIMS used for isotope geology is the national major scientific instruments and equipment development projects. The study of the instrument’s control software is a part of the project. LabVIEW is a high level graphical programming language used extensively in instrumentation, since the software provides high efficiency, process synchronization and code execution parallelization. However, LabVIEW is a structured programming language. As the applications become more large and complex, the expandability, reusability and maintainability of the software become worse. The components of the TOF-SIMS are numerous. Traditional LabVIEW programming method will lead to confused software’s structure. Before LabVIEW introduced the object oriented programming, these problems are solved by improving the structure of the software. However, the effectiveness is limited. In this paper, a control software was developed for TOF-SIMS based on LabVIEW object oriented programming and event-driven communication. TOF-SIMS is composed of many sub-systems including ion optical system, vacuum system, three-dimensional sample stage and ion detection system. The components of these sub-systems include ion lens, ion deflector, ion filter, pulsing ion deflector, Faraday cup motor and so on. All of these components have standard interfaces, including serial port and AD/DA, serial port includes RS485 and RS232. A library of instrument’s control class is built based on the I/O interface types to control all components. A hardware and simulation child class are built for all control class of components. The hardware class is used for components control. The simulation class can not communicate with components but respond simulate value, which could be used for software debugging. Producer/consumer design pattern is used to complete the software structure design. A format of event data is standardizing, which can decrease the impact of change of components. Several user interfaces are shown in the paper to illustrate the function and the design of the software’s front panel. The experiment of zircon which is an important mineral used for geological dating and tracing in geochronology is implemented using TOF-SIMS controlled by the software. The experiment is successfully completed and the spectra of zircon is obtained to proceed subsequent analysis. The results show that the software meets the requirements of the instrument. In addition, the software structure has the advantages of good scalability, easy to develop and to extend, and it is not easy to be affected by hardware change. The software design approach can be used for similar development of instrument control software.